Method for the Protected Transmission of Data, Particularly Transmission Over an Air Interface

1. Method for protected transmission of data packets, the method comprising: a) dividing at least one of the data packets into a sequence of data blocks, dividing at least one of the data blocks into a sequence of data, wherein a coding for each data in said sequence of data is represented by a sequence of a predefined number of on and off values, b) forming a protection datum from the sequence of data and a protection block from the sequence of data blocks, c) generating a first data request to repeat transmission of said sequence of data if the protection datum transmitted together with the data differs from a protection datum formed in a same manner upon receipt of at least one data block, and d) generating a second data request to repeat transmission of said at least one data block if the protection block transmitted together with the data blocks differs from a protection block formed in a same manner upon receipt of at least one data packet.

2. Method as claimed in claim 1 , wherein the sequence of data is followed by a first pause block, and the sequence data blocks are followed by a second pause block.

3. Method as claimed in claim 1 , wherein the protection datum is coded in the same manner as a datum in the sequence of data.

4. Method as claimed in claim 1 , wherein a protection block is formed in a same manner as the sequence of data using protection block data.

5. Method as claimed in claim 1 , wherein the first data request is coded as a first data repeat sequence of a predefined number of on and off values in the first pause block.

6. Method as claimed in claim 1 , wherein the second data request is coded as a second data repeat sequence of a predefined number of on and off values in the second pause block.

7. Method as claimed in claim 5 , wherein the first data repeat sequence differs from the sequence of the predefined number of on and off values.

8. Method as claimed in claim 6 , wherein the second data repeat sequence differs from the sequence of the predefined number of on and off values.

9. Method of claim 1 , wherein the protection datum is formed using a procedure comprising: maintaining a count of the sequence of the predefined number of on and off values; changing a count direction with each on value; and incrementing or decrementing the count based on said count direction with each off value.

10. Method of claim 9 , wherein the count moves cyclically within a hexadecimal range of values 0-F.

11. A mobile data memory for the contactless exchange of protected data packets with a read-write device, having a first coding device, the first coding device comprising: a first comparer operable to generate a first data request if a first protection datum received together with data in the data packet differs from a second protection datum formed in a same manner as the first protection datum from the received data packet, a second comparer operable to generate a second data request if a first protection block of the data packet received together with data blocks differs from a second protection block formed in a same manner as the first protection block from the received data blocks, a first querier operable to repeat previously transmitted data after detection of a first data request, and a second querier operable to repeat previously transmitted data blocks after detection of a second data request.

12. A read-write device for the contactless exchange of protected data packets with a second mobile data memory, having a second coding device, the second coding device comprising: a third comparer operable to generate a first data request if a first protection datum received together with data of the data packet differs from a second protection datum formed in a same manner as the first protection datum from the received data packet, a fourth comparer operable to generate a second data request if a first protection block of the data packet received together with data blocks differs from a second protection block formed in a same manner as the first protection block from the received data blocks, a third querier, operable to repeat previously transmitted data after detection of a first data request, and a fourth querier, operable to repeat previously transmitted data blocks after detection of a second data request.

13. An identification system comprising: a mobile data memory for the contactless exchange of protected data packets with a read-write device, having a first coding device, and a read-write device for the contactless exchange of protected data packets with a second mobile data memory, having a second coding device, the first coding device further comprising: a first comparer operable to generate a first data request if a protection datum received together with data in the data packet differs from a protection datum formed in a same manner, a second comparer operable to generate a second data request if a protection block of the data packet received together with data blocks differs from a protection block formed in a same manner, a first querier operable to repeat previously transmitted data after detection of a first data request, and a second querier operable to repeat previously transmitted data blocks after detection of a second data request, the second coding device further comprising: a third comparer operable to generate a first data request if a protection datum received together with data of the data packet differs from a protection datum formed in a same manner, a fourth comparer operable to generate a second data request if the protection block of the data packet received together with data blocks differs from a protection block formed in a same manner, a third querier, operable to repeat previously transmitted data after detection of a first data request, and a fourth querier, operable to repeat previously transmitted data blocks after detection of a second data request, wherein the read-write device and the data memory are together operable to exchange data packets via a contactless data transmission link.

14. The identification system of claim 13 wherein the exchange of data is based on ISO/IEC Standard 14443 for operation in an ISM frequency band.

15. The identification system of claim 13 wherein the exchange of data is based on ISO/IEC Standard 15693 for operation in an ISM frequency band.

16. The identification system of claim 14 , wherein the ISM frequency band is of a wavelength of 13.56 MHz.

17. The identification system of claim 15 , wherein the ISM frequency band is of a wavelength of 13.56 MHz.